Is this Rosette disease?

Is this Rosette disease?

Thu Apr 19, 2018 10:55 pm

I’ve never had roses before and somebody gave me two Knockout Roses as a gift. I tried to do some reading up about them before planting them so I know what to expect and what I need to be doing. I came across information on this disease and I’m concerned that one of the two plants seems to exhibit similar symptoms— purple leaves, some yellow and brown blotches on leaves, more thorns on the branches with the red/purple leaves, etc. Can somebody who actually knows what they’re doing please look at these photos and tell me if I’m dealing with this?

Re: Is this Rosette disease?

Sun Apr 22, 2018 9:36 pm

No, lucky you! One of my roses got it this year. Expect way more out of control growth at the ends; dark pinks on messy growth; too many thorns; etc. Pic 2 is just normal coloring at this time of the year.

Re: Is this Rosette disease?

Mon Apr 23, 2018 7:05 am

Thanks. My sister first "got it" with her roses approx 2-4 years ago. A neighbor of mine got it this year or last. I had not noticed her problem until I saw the witches broom growth in mine. This area is like RRD Central and many plant nurseries have dropped sales of roses. People need to yank them and dispose of them asap but people and commercial buildings do not usually do that... local rose societies and meetings with universities suggest to throw them away in plastic trash bags... the plastic trash bag is 'small' attempt to halt the progression but frankly, what do you think will happen to those plastic bags if you put a thorny shrub like a rose inside? Of course, it will get punctured with holes... It was a pain in the neck (difficult, thick at the bottom as it was a tad old rose) cutting my shrub... and luckily for me that it was not thaaat big. But I had planted it in honor of a pooch that has since passed away so that also "lit a firecracker". Ha! Yes, of all the other 70+ roses, it had to choose that one. Brother.

Below are links to a few sample RRD pictures. The 2nd shows stems with waaaay too many thorns; sometimes you even see these thorns develop in the bloom's sepals (the little 'leaves' attached to the flower bud). The third one shows -a little- how the RRD-infected stems (typically at the ends) can appear to be wider or "thicker"; see if you can tell the thinner width of green & normal looking stems below the wider RRD stems.The third one also shows the typical color; there is little photosynthesis going on in RRD plant materials so they stay looking shades of red or purple way longer than in good green growth... but eventually all or most of the red/purples will green out.

Technically, when you see the "out of control" RRD growth, the whole plant is infected, including the parts that still may look normal. That is why they ask you throw it away in the trash, so the issue does not get passed on to other nearby rose bushes.

Re: Is this Rosette disease?

Mon May 07, 2018 2:51 am

I hope it's ok for me to ask this question too here. I saw this thread was recently made and I thought instead of making a new thread posting here would be better. I'm having a hard time telling if my Rio Rosa has rosette disease.